Andre Villas-Boas is sure Harry Redknapp will keep QPR up, but he has told his predecessor to forget the idea of bolstering his struggling strikeforce with a January bid for Jermain Defoe.

Redknapp's five-month absence from football came to an end on Saturday when he signed a two-and-a-half year contract with Barclays Premier League basement boys QPR.

The 65-year-old immediately highlighted a lack of firepower up front as his main concern, with Andy Johnson and Bobby Zamora both out with long-term injuries.

That immediately sparked speculation linking Redknapp with Defoe - a striker with whom he has worked at Tottenham, West Ham and Portsmouth.

But Defoe, often overlooked by Redknapp last season, has thrived under Villas-Boas this term and the Portuguese has no intention of letting the 30-year-old leave.

"That's not possible," Villas-Boas said when asked about the prospect of Defoe leaving in January.

"It's absolutely impossible. We have the belief in him."

The Tottenham manager's belief in Defoe is so strong that he even considers the England striker to be on a par with Radamel Falcao - the Colombian striker who scored bags of goals for Villas-Boas at FC Porto and is now setting the Spanish league alight with Atletico Madrid.

"He is one of the best strikers I have worked with," Villas-Boas said of Defoe, who has scored 10 times for Spurs this year.

"I certainly put him alongside Falcao.

"His hunger for goal is extreme. That makes things easier for you to work with because you don't have to teach a lot.

"I don't have a lot of experience. The experience I have is with a couple of strikers, but I put him up there with the best.

"He smells every cross and when the opportunity is there to tap it in.

"Plus he has the ability to turn on the defenders and he still has the pace in him to cause chaos."

Villas-Boas refused to take a similar stance on Michael Dawson, however.

Dawson turned down a £9million move to Loftus Road in the summer, but Redknapp is thought to be interested in signing the Spurs skipper in January.

"I think if that possibility arises we will have to consider it," said Villas-Boas, who has only given Dawson one league start this term.

"But we're not looking to make a lot in the January transfer window."

Villas-Boas is all too aware of the high expectations placed upon him after Redknapp guided Tottenham to fourth, fifth and fourth during his three full seasons at the north London club.

The Portuguese could be forgiven for bemoaning Redknapp's return to top-flight football, but the Spurs boss is happy to see his predecessor back in the game - and he has no doubt the west London club will survive under his leadership.

"It's good for the game that he is back," Villas-Boas said.

"He's a manager with more experience in the Premier League, a respected manager who is used to making impossible things turn possible.

"It is the kind of challenge that makes him even more motivated.

"I would put on a bet if I could that they would save themselves."

Villas-Boas' attempt at delivering the top-four finish demanded of him will face a stern test tomorrow night when Spurs host Liverpool.

The Londoners arrested a three-match losing streak with victory over West Ham on Sunday, with Clint Dempsey turning in his best performance since moving to White Hart Lane from Fulham this summer.

The American had struggled to settle in to the Tottenham team, but he helped set up two of the team's goals with an impressive display just behind Defoe.

Villas-Boas is glad Dempsey's on-off move to Liverpool this summer failed to materialise.

"It was a masterclass from our chairman to sign him," Villas-Boas said.

"I gave the green light to do it and I think we did extremely well.

"Sunday was his first full individual 90 minute performance and that was important for him. He has been looking for it to happen for some time."